From 0c4434d088fcee41461190faec00194f6913acfb Mon Sep 17 00:00:00 2001
From: Ruben Dashyan <ruben.dashyan@numworks.com>
Date: Tue, 17 Mar 2020 10:17:42 +0100
Subject: [PATCH] [poincare/expression] getUnit returns an uninitialized
 Expression

when there is no Unit instead of Undefined
---
 poincare/src/addition.cpp               | 6 +++++-
 poincare/src/expression_node.cpp        | 2 +-
 poincare/src/multiplication.cpp         | 4 ++--
 poincare/src/power.cpp                  | 2 +-
 poincare/src/unit_convert.cpp           | 2 +-
 poincare/test/expression_properties.cpp | 2 +-
 6 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/poincare/src/addition.cpp b/poincare/src/addition.cpp
index 5d99cce4b..02167bf56 100644
--- a/poincare/src/addition.cpp
+++ b/poincare/src/addition.cpp
@@ -160,8 +160,12 @@ Expression Addition::shallowReduce(ExpressionNode::ReductionContext reductionCon
    * the result is not homogeneous. */
   {
     Expression unit = childAtIndex(0).getUnit();
+    const bool hasUnit = !unit.isUninitialized();
     for (int i = 1; i < childrenCount; i++) {
-      if (!unit.isIdenticalTo(childAtIndex(i).getUnit())) {
+      Expression otherUnit = childAtIndex(i).getUnit();
+      if (hasUnit == otherUnit.isUninitialized() ||
+          (hasUnit && !unit.isIdenticalTo(otherUnit)))
+      {
         return replaceWithUndefinedInPlace();
       }
     }
diff --git a/poincare/src/expression_node.cpp b/poincare/src/expression_node.cpp
index 94115d40e..1ac78e729 100644
--- a/poincare/src/expression_node.cpp
+++ b/poincare/src/expression_node.cpp
@@ -137,7 +137,7 @@ bool ExpressionNode::isOfType(Type * types, int length) const {
 }
 
 Expression ExpressionNode::getUnit() const {
-  return Undefined::Builder();
+  return Expression();
 }
 
 void ExpressionNode::setChildrenInPlace(Expression other) {
diff --git a/poincare/src/multiplication.cpp b/poincare/src/multiplication.cpp
index 68e366239..14ba43034 100644
--- a/poincare/src/multiplication.cpp
+++ b/poincare/src/multiplication.cpp
@@ -264,13 +264,13 @@ Expression Multiplication::getUnit() const {
   int resultChildrenCount = 0;
   for (int i = 0; i < childrenCount; i++) {
     Expression currentUnit = childAtIndex(i).getUnit();
-    if (!currentUnit.isUndefined()) {
+    if (!currentUnit.isUninitialized()) {
       result.addChildAtIndexInPlace(currentUnit, resultChildrenCount, resultChildrenCount);
       resultChildrenCount++;
     }
   }
   if (resultChildrenCount == 0) {
-    return Undefined::Builder();
+    return Expression();
   }
   return std::move(result);
 }
diff --git a/poincare/src/power.cpp b/poincare/src/power.cpp
index da0579f72..d6f27e7bb 100644
--- a/poincare/src/power.cpp
+++ b/poincare/src/power.cpp
@@ -987,7 +987,7 @@ Expression Power::getUnit() const {
     return clone();
   }
   Expression baseUnit = childAtIndex(0).getUnit();
-  if (baseUnit.isUndefined()) {
+  if (baseUnit.isUninitialized()) {
     return baseUnit;
   }
   return Power::Builder(baseUnit, childAtIndex(1).clone());
diff --git a/poincare/src/unit_convert.cpp b/poincare/src/unit_convert.cpp
index 4dfc699ba..0002bb500 100644
--- a/poincare/src/unit_convert.cpp
+++ b/poincare/src/unit_convert.cpp
@@ -42,7 +42,7 @@ Expression UnitConvert::shallowReduce(ExpressionNode::ReductionContext reduction
         reductionContext.target(),
         ExpressionNode::SymbolicComputation::ReplaceAllSymbolsWithUndefinedAndReplaceUnits);
     Expression unit = childAtIndex(1).clone().reduce(reductionContextWithUnits).getUnit();
-    if (unit.isUndefined()) {
+    if (unit.isUninitialized()) {
       // There is no unit on the right
       return replaceWithUndefinedInPlace();
     }
diff --git a/poincare/test/expression_properties.cpp b/poincare/test/expression_properties.cpp
index 88f49370f..854888d5b 100644
--- a/poincare/test/expression_properties.cpp
+++ b/poincare/test/expression_properties.cpp
@@ -378,7 +378,7 @@ void assert_reduced_expression_unit(const char * expression, const char * unit,
   Expression u2 = parse_expression(unit, &globalContext, false);
   u2 = u2.reduce(redContext);
   u2 = u2.getUnit();
-  quiz_assert_print_if_failure(u1.isIdenticalTo(u2), expression);
+  quiz_assert_print_if_failure(u1.isUninitialized() == u2.isUninitialized() && (u1.isUninitialized() || u1.isIdenticalTo(u2)), expression);
 }
 
 QUIZ_CASE(poincare_properties_get_unit) {